This invention relates generally to radiation detectors and, more specifically, to a suspension and protection system for a radiation detector enclosed within a housing.
Existing radiation detectors are often subjected to varying degrees of shock and/or vibration during normal usage. In some cases, the degree of shock and/or vibration exposure may be quite severe. Deleterious effects from shock and/or vibration may include high background counts, noise in the detector's response spectrum, and even breakage of the detector.
Existing shock and vibration isolation systems for radiation detectors typically include either an elastomeric boot that is telescoped over the radiation detector, or a foam pad that is wrapped around the radiation detector. Recently, some detectors have been designed with a suspension system including flat springs made from spring steel placed along the length of the detector in spaced circumferentially about the diameter of the detector. This has the effect of using the springs as a simply supported type beam, flexed between the OD of the radiation detector and the ID of its housing. These springs then absorb as well as transmit without amplification the shock and vibration that the detector experiences. Additionally, they lock the detector into place to prevent the detector from moving radially inside of its housing. This arrangement has been shown to provide higher degrees of shock and vibration protection than the elastomeric and foam types of suspension systems. Additionally, the radial spring-type suspension makes it possible to package a larger size radiation detector into the same size outer envelope than would normally be possible with elastomers or foam padding.
There are two main drawbacks associated with radial spring suspension systems of the type described above. The first drawback arises from the attenuation of the gamma rays as they pass through the (spring) steel springs. This prohibits the measurement of low energy gamma radiation (below 60 KeV). The second drawback comes from detectors with electrical insulation located radially between the outside of the detector and the inside of the housing. In this case, the steel springs conduct electricity, thereby undesirably forming a circuit between the detector's outer diameter and the housing's inner diameter.
By replacing the spring steel with a material that attenuates the gamma rays less, but still provides a comparable degree of shock and vibration isolation, a detector can be constructed that will exhibit significantly better performance at low energy gamma levels, i.e., below 60 KeV. Using non-metallic springs also prevents formation of the aforementioned electrical circuit.